Oh how I love piezoeletric materials, the kind that generate electricity when squeezed. Unfortuantely, the best substances that exhibit that characteristic are toxic and hard to work with. So, a group at the Lawrence Berkeley National Laboratory is developing a greener alternative that uses a bacteria-eating virus instead.
The piezoelectric effect has the potential for paper-thin generators that we power with human movements. Unfortunately, the best-performing piezoelectric materials contain lead, a no-no for consumer electronics, as the Swiss National Science Foundation points out. The Berkeley Lab group, led by faculty scientist and U.C. Berkeley associate professor of bioengineering Seung-Wuk Lee, turned to the M13 bacteriophage.
This bacteriophage is a common virus harmless to humans that attacks bacteria. Bioengineers really like it because the phage replicates quickly and can be genetically engineered easily. Turns out that it's also piezoelectric. To create their generator, the Berkeley Lab scientists engineered the phage to boost its electrical output when squeezed and then stacked thin films containing single layers of the virus.
In the lab, the bacteria-based generator successfully converted the force of a finger tap into an electrical charge. They found that it can produce up to 6 nanoamps of current and 400 millivolts of potential, according to their published research, which is about a quarter of a AAA battery's voltage. That's also enough to be used to operate a small liquid-crystal display.
The group first published their results in Nature Nanotechnology (abstract) last May, but for some weird reason the news was dormant since then. Hat tip to Inhabitat's Timon Singh for shining a light on the development.
In their Nature paper, the scientists write that harmless virus-based piezoelectric materials potentially "offer a simple and environmentally friendly approach to piezoelectric energy generation." I can't wait until they scale it up. Imagine all that frantic keyboard tapping actually charging your laptop.
Photo: A harmless bacteria-eating virus could let your fingers do the walking. Credit: Lawrence Berkeley National Laboratory